I wonder if it is a quality control issue.
Could be. My friend has the same rest on his bow right now and wanted another for another outfit he has....his has been quieter from day one than mine was.....I'm not at all upset about getting rid of it. I've noticed my pick up arm is much farther towards the riser than his(alum. cradle is in turn farther from the riser) and some other minor things, but all in all I think one could/should buy a much better rest.